Apparatus. Prototype ThermoSorb/N cartridges (Therm0 Electron Corp.) were tested when they were received. The cartridges were constructed of medicalgrade
polyethylene with IOO-mesh stainless-steel screens at the inlet and outlet and had standard Luer fittings to facilitate solvent elution of the trapped materials. The sorbent bed (20 mm deep and 15 mm ID) contained a mixture of magnesium silicate and an
amine trapping (complexingj agent and nitrosation inhibitor.